A computed tomography (CT) scanner includes an x-ray tube that emits radiation that traverses an examination region and a portion of an object or subject therein. A detector detects radiation traversing the examination region and generates projection data indicative of the detected radiation. A reconstructor reconstructs the projection data and generates volumetric image data indicative of the portion of the object or subject in the examination region.
A cardiac CT scan for coronary calcium is a non-invasive way of obtaining information about the presence, location and extent of calcified plaque in the coronary arteries. Generally, calcified plaque is build-up of fat and/or other substances under the inner layer of the artery and may indicate a presence of atherosclerosis, or coronary artery disease, which indicates a risk of heart attack. Since calcium is a marker of coronary artery disease, the amount of calcium in CT data has been quantified as a calcium score through a procedure generally referred to as calcium scoring.
Conventionally, two main calcium scoring approaches exist. The first is automatic calcium scoring, which is done globally, so there is one global calcium score. The other is manual calcium scoring in which a user employs a software application to manually distinguish different regions of the coronary arteries and calcium scores are determined for the different regions. Unfortunately, such methods do not always provide the granularity of interest for all patients.
For example, for minimally invasive aortic valve implantation, the spatial distribution of calcified plaque around the aortic valve, aortic bulbus, leftventricular outflow tract and aorta is important for risk assessment and planning of the procedure. Calcium in the aorta determines the access method; the amount of calcium on the valve has an influence on the selection of the right diameter of the stent; distribution of calcium on the three (3) leaflets can have an influence on stent stability; calcium on the leftventricular outflow tract has an influence on the stability of the implanted stent.
In view of the above, there is an unresolved need for novel and non-obvious calcium scoring approaches.